Polyamide fiber cords are widely used as a reinforcing material for industrial rubber articles such as tires, conveyor belts, hoses, air springs and the like because they have excellent strength, durability, and heat resistance among various reinforcing cord materials.
Polyamide fiber cords are subjected to a so-called “dip treating step” in which the cords are immersed in an adhesive solution required for the adhesion between fiber and rubber, dried, and heated under tension at a high temperature near the melting point of the fiber. In addition to requiring this further dip treating step, the materials used to prepare the adhesive solution, such as resorcinol and formaldehyde, add cost and increase manufacturing time.
There is a need to decrease the amount of the adhesive material used in the dip treating step or eliminate the dip treating step from the viewpoint of weight reduction of the tire, reduced costs, and improved productivity.
It is an objective of the present disclosure to alleviate or overcome one or more difficulties related to the prior art. It has been found that functionalized polyamides can be used in tire cords that include terminal free thiols to crosslink directly with rubber, which leads to the reduction or elimination of the dip treating step.